Louise Daugherty Added comment: Comment on list classification: New gene added by external expert and reviewed by curation team, enough evidence to support gene-disease association and relevance to this panel to rate this gene Green. From PMID: 29375865 (2018) A. Abhyankar et al. summarised Ruzzo et al. (PMID:24139043) studied nine children from four families presenting with similar phenotypes and reported two missense mutations‐c.1084T>G (p.F362V; NM_183356) and c.1648C>T (p.R550C; NM_183356) in the asparagine synthetase domain that dramatically reduce ASNS protein abundance. The authors concluded that accumulation of aspartate/glutamate secondary to ASNS depletion in the brain resulted in the neurologic impairment. One of the two mutations reported in that study, c.1084T>G (p.F362V; NM_183356), is four residues upstream of NP_001664.3:p.Gly366Glu seen in our patient. HEK293 cells expressing c.1084T>G (p.F362V; NM_183356) mutant allele showed dramatic reduction in protein abundance. Additionally, Ruzzo et al. reported a hypomorphic ASNS mouse knockout with structural brain abnormalities and deficits in learning/memory. Subsequently, eight more cases of ASNSD have been reported in the literature PMID: 2566342,27422383, 27469131, 27743885.
Louise Daugherty commented on gene: ASNS: Comment on publications: Added GeneReview PMID: 30234940 (2018) for Asparagine Synthetase Deficiency and PMID:27743885 (2017) first two cases (related) Japanese patients with ASNS deficiency with developmental delay and PMID: 29375865 (2017) reports two novel compound heterozygous missense variants in asparagine synthetase gene as the likely cause of fatal asparagine synthetase deficiency in a single neonate case.
Louise Daugherty Phenotypes for gene: ASNS were changed from Asparagine synthetase deficiency, 615574; congenital microcephaly, severe developmental delay, and axial hypotonia followed by spastic quadriplegia to Asparagine synthetase deficiency, 615574; congenital microcephaly, intellectual disability, progressive cerebral atrophy, intractable seizures
Louise Daugherty Added comment: Comment on publications: Added GeneReview PMID: 30234940 (2018) for Asparagine Synthetase Deficiency and PMID:27743885 (2017) first two cases (related) Japanese patients with ASNS deficiency with developmental delay
Louise Daugherty Phenotypes for gene: ASNS were changed from Asparagine synthetase deficiency, 615574 to Asparagine synthetase deficiency, 615574; congenital microcephaly, severe developmental delay, and axial hypotonia followed by spastic quadriplegia